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Old March 21st 06, 06:29 AM posted to rec.radio.amateur.boatanchors
Edward Greeley
 
Posts: n/a
Default Hallicrafters S-20R alignment

Er...it's late, and maybe my thinking is a bit muddled, but: it sounds
to me like you need to get the oscillator freq LOWER than it is now
going. The earlier follow-on posts seem to be discussing ways to get the
oscillator freq HIGHER - unwanted extra capacitors, inability to loosen
the trimmer sufficiently, wrong slugs (which you don't have), etc. In my
muddled little mind, it seems you need MORE capacity and/or coil
inductance to get the oscillator freq LOWER, i.e. the oscillator needs
to be at 7.0 MHz + 455 KHz = 7.455 MHz rather than 7.5 MHz + 455 KHz =
7.955 MHz as you now have it. So, is there a chance that there is
supposed to be a little fixed ceramic or mica capacitor in parallel with
the adjustable trimmer cap across the oscillator coil that is open,
broken, or missing? Again, you need to get the oscillator freq LOWER,
not higher, don't you? Okay, so broken is the same as open; I said it's
late!

Good luck!
Ed Greeley

Skyrider wrote:

I am having a problem aligning an S 20R. The receiver has just been
re-capped, however the problem I have been having was present before
the set was touched. (The set just has much better sensitivity and the
transformer runs cooler now). The problem I have been having is this:
When I try to align on band 3 (the only band which gives problems) the
closest I can bring it to proper alignment puts 7 Mhz at around 7.5 or
so on the dial, and 10 MHz at about 12 Mhz on the dial. I cannot bring
the dial tracking any closer than this. The other bands seem OK. I
have checked the wiring against a parts receiver and do not see any
problems. I verified that the oscillator is 455kHz above the received
frequency by checking a known working S 20R (which I have owned for 36
years). There does not appear to be any problem with the
trimmer/padder caps or the coil.

Any ideas???